Many businesses utilize mainframe or minicomputers such as IBM mainframes, the Hewlett Packard HP3000, the IBM AS/400, and Digital Equipment Corporation VAX computers to maintain and manipulate essential information, such as accounting data. At one time, access to the programs, and therefore the data, was available only through dedicated terminals, which were connected directly to the computer or to a network on which the computers resided. However, as the use of personal computers in businesses became widespread, terminal emulation programs were developed that ran on personal computers. A terminal emulation program allows a personal computer (PC) to function as a terminal to a host mainframe or minicomputer. The PC monitor displays the information that a dedicated host terminal would display, while alphanumeric data entered with the PC is passed to the host computer in the same manner as if the data were entered with a dedicated terminal.
The RUMBA.RTM. connectivity software, developed by Wall Data Incorporated, is a computer program that establishes a communications link between a PC and a host computer. The RUMBA software allows the user of a PC to connect to a host computer in order to view stored data and enter new data. RUMBA provides a window on the PC within which an operator can access and manipulate data from a host computer. The communications link and window are referred to as a RUMBA session. The host computer creates a memory buffer containing data that is displayed on the host terminal, if such a terminal is used. The visual representation of the host memory buffer is referred to as a presentation space, and is displayed within a RUMBA window that can be manipulated utilizing standard Windows techniques, such as resizing or moving the window.
In recent years, there has been a tremendous proliferation of computers connected to a global network known as the Internet. A computer connected to the Internet can download digital information from special computers connected to the Internet called World Wide Web servers. These servers allow other computers to execute a Web browser program that translates the digital information into a visual form that is perceptible by a user.
Documents that can be retrieved from a computer on the Internet generally containing instructions in a format known as "Hypertext Markup Language" (HTML). These instructions allow a computer that is running a Web browser to view the document. HTML includes instructions for formatting text, linking to digital data, and receiving input from a user at a client computer. HTML is designed to be platform independent, so a Web page can be displayed on any computer with a compatible browser program.
The Web server transmits an HTML document over the Internet to client computers. Typically, a Web server includes multiple HTML documents, each page being stored in a file on the Web server's disk or other storage mechanism.
In addition to the Internet, another computer configuration that is becoming increasingly popular is called an "intranet." An intranet operates in the same manner as the Internet, except that client computers and servers are connected together through a local area network (LAN), which allows limited access from computers that are not coupled directly to the LAN. Typically, an intranet is used within a single corporation or other organization.
Markup languages, such as HTML, provide limited capabilities. Unlike regular programming languages, markup languages are designed to specify the formatting information necessary to present information. They do not have the dynamic capabilities of a regular programming language. JavaScript is a scripting language that is used to extend the capabilities of HTML. JavaScript is capable of recognizing and responding to events, such as mouse clicks and movements, generated by a browser program. JavaScript scripts are embedded in HTML documents. The browser executes each script as it reaches the position of the script during interpretation of the HTML document. JavaScript scripts are transferred between a server and a browser as text and interpreted by the browser program.
Currently existing methods of accessing information from host computers require the time and expense of physically linking client computers with host computers. It is desirable to have a method of providing access to host computers from remote locations. It is also desirable that such a method provide a user interface that is easy to use.